Schedule HDMI input switching on a lobby screen

How do you put a camera feed on a lobby screen on a schedule?

Let hardware carry the schedule: an auto-sensing HDMI switcher sits between the signage player and the camera feed, and a timer outlet powers the feed only for the service window, so the screen lands on the feed at the start and falls back to signage at the end.

The problem is standard for any lobby and reception display that shares its time between a playlist and a live source, so the fix is to move the switching into hardware you set once. The route that tempts everyone first, feeding the camera into the player and scheduling it there, is closed: a signage player's HDMI port is an output, and the article on HDMI input on Android signage players explains what happens when you try it. So the switch happens after the player: camera feed and player both feed the switcher, and the switcher's single output feeds the screen.

An auto-sensing switcher watches its inputs for a newly active signal and moves to it; when that signal drops, it falls back to the input that is still live. The player never notices and keeps rendering into an input the screen is not showing, so the signage playlist needs no changes. Confirm the switcher's manual lists an auto or auto-sense mode before you buy: a basic box that switches only on demand cannot carry this schedule.

Why not just send CEC input commands from the player?

Treat scheduled CEC input switching as the last resort: the HDMI standard defines the active-source command, but screens implement it unevenly, so a command that switches one screen works on the bench and is ignored on the next screen you hang.

CEC is the control channel that rides inside the HDMI cable, carrying commands such as standby, wake and active source between devices. Power commands are the ones screens honor most consistently, which is why CEC power switching has a good reputation. Selecting an input is where implementations diverge: the active-source command one screen obeys instantly is ignored by the next, and reports of that go back years across many source and screen combinations. The honest test is per screen, on the exact pair you will run.

The sending side is the second problem. An offline media player that renders a playlist from a card has no documented way to fire a command at 09:55; the digital signage player guide covers what these players are designed to do. Builds that bridge a small single-board computer to the screen's CEC line do exist, but they add a second computer to maintain, and a screen firmware update can change what the command does. If a player you already own can send CEC on a schedule, bench-test the exact pair twice before you depend on it. Otherwise let the switcher do the switching.

What hardware does the scheduled switch need?

You need three things: a 2-in auto-sensing HDMI switcher, a weekly timer outlet, and HDMI cables that keep every passive run at about 10 m for a 1080p feed.

• Switcher: rated for at least 1080p60; a 4K-rated model covers it too. Two inputs carry a player and a feed, and a 4-input unit leaves a spare for a laptop. Auto mode is the feature that matters.
• Timer outlet: a weekly digital timer, so each day can carry its own window and unused days stay off. A small camera encoder draws under 20 W, well inside what any household timer outlet switches.
• Cables: passive copper HDMI handles 1080p dependably up to about 10 m, and longer runs are where dropouts start. Keep both runs inside that budget, use an active HDMI cable for a longer one, or decode a network camera to HDMI near the screen.
• Mounting: the switcher goes on a shelf or in a cabinet near the screen, with its own mains outlet. A screen hung on our low-profile bracket sits about 12 mm off the wall, too close for a switcher box behind it; the mounting and power accessories page covers that bracket.

Power the switcher from a normal outlet and leave it powered. The timer belongs on the camera source only.

How do you set it up step by step?

Setup takes about 30 minutes: wire the sources into the switcher, set the switcher to auto mode, put the camera source on the timer outlet with five minutes of margin at each end, then run one full test cycle before the real window.

1. Read the switcher manual far enough to confirm the auto mode and how it picks an input, then wire the camera or encoder into input 1, the signage player into input 2, and the output to the screen.
2. Put the camera source on the weekly timer outlet and confirm the switcher keeps mains power of its own, never on the timer.
3. Set the weekly timer: on at the window start minus 5 minutes, off at the window end plus 5. If the source is a disk recorder that also stores footage, use its own output schedule instead of hard power cuts; sudden power loss can corrupt recordings.
4. Set the switcher to auto mode, then power the camera source once by hand and confirm the switch lands on it.
5. Rehearse the full cycle in daytime: let the timer cut the encoder off and watch signage return.
6. If the switch lands on the wrong input while both sources are live, move the camera to the switcher's priority input, or move that pair to the RS-232 route below.

What does an example schedule look like for a 90-minute service?

Set the timer for 09:55 on and 11:35 off: the 90-minute service gets five minutes of margin at each end, the encoder is powered for 100 minutes in total, and the whole schedule produces exactly two switches.

Here is the timeline for one service, with the arithmetic shown.

• 09:55: the timer closes and the encoder takes power. A small encoder boots in about a minute.
• About 09:56: the encoder starts its 1080p60 output. The switcher sees the new signal on input 1 and switches, the screen re-locks in two to five seconds, and the feed is on the wall four minutes before the service starts.
• 10:00 to 11:30: the service plays from the camera. Powered time is 90 + 5 + 5 = 100 minutes.
• 11:35: the timer opens, the HDMI signal drops, and the switcher falls back to input 2, where the player has been rendering the whole time. Signage is back within about five seconds.

Two switches per service, nobody near a remote, and the signage playlist untouched. For a second weekly window, say 18:30 to 20:00 on Wednesdays, program another event pair on the same timer: on at 18:25, off at 20:05.

How do you check that the schedule worked?

Run the rehearsal at midday, not five minutes before the doors open: power the encoder, count the seconds of blank screen, confirm the feed lands, then cut the encoder power and confirm signage returns on its own in a few seconds.

• Run the cycle twice. The second switch, back to signage, is the one that gets forgotten, and it is the one the whole room watches at 11:35.
• Most switchers mark the active input with an LED. Glance at it during the rehearsal so you know which lamp means the feed is live.
• Note the blank time between switch and picture. If the pair takes longer than about five seconds, widen the timer margin from five minutes to ten so nobody watches a blank screen.
• After any building power cut, check the timer clock. Simple digital timers lose their program when power is gone, and the schedule silently moves with the clock.

When does an RS-232 controlled switcher make more sense?

When the camera source must stay powered, use a switcher with RS-232 or LAN control and let a scheduled command select the input; a PC-based player can run that schedule, an offline card-playing media player cannot.

Rack-style switchers list an RS-232 and LAN control set in their manuals, with the command strings and the serial settings printed there. Take the strings from that manual exactly. A PC-based player carries the schedule: its task scheduler fires a small script at 09:55 and 11:35 that sends the input-select string out of a serial port, or through a serial-to-Ethernet converter when the switcher sits across the room. The LAN route is the same over the network.

Choose this route when the source cannot be power-cycled: a disk recorder that serves other jobs through the week, or a feed a second screen also needs. It is also the cure when one particular source and switcher fight over auto priority.

The offline card-playing media player sits this route out, because it has no command output designed into it.

What if the feed does not have to be live?

If the room does not need the feed live, skip the switcher: record it once, drop the file on the player and schedule it in the playlist like any other content, which removes the timer, the switcher and the blank screens.

Recording is the quiet option: capture the service once, put the file on the player like any other content, and let the playlist carry the window. Nothing extra hangs on the wall and nothing extra can fail on a Sunday morning. The article on exporting slides to video for an offline signage player covers getting files into a shape an offline player handles well.

For a genuinely live source, watch the network trap: an IP camera's RTSP stream will not play on an Android signage player, which the article on RTSP streams and Android signage players explains, so a network camera needs a decoder that outputs HDMI before the switcher can select it. The wider picture of getting live content onto these screens is in the article on displaying a live dashboard on a signage screen.

Recommendation: for a fixed weekly window, buy a 2-input or 4-input auto-sensing HDMI switcher rated at least 1080p60, power the camera feed from a weekly timer outlet set five minutes either side of the window, and leave CEC out of the design. Move to an RS-232 or LAN-controlled switcher with scheduled commands from a PC-based player when the source must stay powered or the auto mode picks the wrong input.

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